Lifetimes of image-potential states on copper surfaces

TL;DR

This paper presents a theoretical study of the lifetimes of image-potential states on copper surfaces, using many-body perturbation theory and realistic models, achieving results consistent with experimental data.

Contribution

It introduces a detailed theoretical approach combining GW approximation and RPA to accurately compute surface state lifetimes on copper.

Findings

Theoretical lifetimes agree well with experimental measurements.

The GW and RPA methods effectively model quasiparticle decay.

Surface state decay times are quantitatively predicted.

Abstract

The lifetime of image states, which represent a key quantity to probe the coupling of surface electronic states with the solid substrate, have been recently determined for quantum numbers $n\le 6$ on Cu(100) by using time-resolved two-photon photoemission in combination with the coherent excitation of several states (U. H\"ofer et al, Science 277, 1480 (1997)). We here report theoretical investigations of the lifetime of image states on copper surfaces. We evaluate the lifetimes from the knowledge of the self-energy of the excited quasiparticle, which we compute within the GW approximation of many-body theory. Single-particle wave functions are obtained by solving the Schr\"odinger equation with a realistic one-dimensional model potential, and the screened interaction is evaluated in the random-phase approximation (RPA). Our results are in good agreement with the experimentally determined decay times.